She is canonically (but not IRL) the elder sister of Selen Tatsuki, who debuted in the 2nd batch of Nijisanji EN.
See post #4794881.
Elira has long blue hair, with white trim, blue head wings, x hair ornament and bangs covering her left eye. Her right eye is aqua, while her character sheet revealed that she shares her sister's heterochromia with her left eye being purple. She also has prominent fangs.
For her outfits, see their respective pages.
- Pikl, a dragon that always besides Elira. It wears a necklace which spells "QUEEN." Along with Elira's casual outfit reveal, it got a brown and purple scarf and a monocle with a strap